Multiple plane scanning system for data reading applications

ABSTRACT

An optical system and method for data reading. The preferred system is directed to a scanner which includes a multiple beam source, such as a laser diode and a beam splitter which generates first optical beam and a second optical beam, the first optical beam being directed toward one side of a scanning optical element such as a rotating polygon mirror and to a first mirror array, the second optical beam is being simultaneously directed toward a second optical element such as another side of the rotating polygon mirror and then to a second and a third mirror array. The first mirror array is configured to generate a scan pattern through a vertical window and the second and third arrays are configured to generate scan patterns passing through a horizontal window. In combination, the three mirror arrays generate three sets of scan lines so as to scan the bottom and all lateral sides of an object being passed through the scan volume.

RELATED APPLICATION DATA

This application is a Divisional of Ser. No. 08/554,819 filed Nov. 7,1995 now U.S. Pat. No. 5,705,802 which is a divisional of Ser. No.08/155,112 filed Nov. 19, 1993 now U.S. Pat. No. 5,495,207 which is acontinuation of part of application Ser. No. 07/913,580 filed Jul. 14,1992 now abandoned.

BACKGROUND OF THE INVENTION

The field of the present invention relates to optical scanning systemsand particularly to a scanning system capable of successfully readingobjects aligned in a variety of orientations. The invention isespecially suitable for use as a fixed scanner such as that employed ata supermarket checkout counter reading bar codes such as those found onconsumer products.

For effective and accurate performance, a bar code scanner depends uponfocused optics and scanning geometry. Fixed scanners frequently employ arotating polygon mirror which directs a scanning beam toward a mirrorarray for generating a desired scan pattern. One type of fixed bar codescanner positions a scan engine in a base with a scan window oriented ina horizontal plane. One such scanning system is disclosed in U.S. Pat.No. 5,073,702 in which a scanning beam is reflected off a mirror arraywhich has a plurality of mirrors arranged in a generally semicircularpattern. The scanning beam reflecting off each of the mirrors hasvertically upward component thereby passing through the window/aperture.Objects to be scanned are passed over the window with the bar codesoriented in a generally downward direction.

In another scanner orientation, the scan engine is housed in a verticaltower with the scan window oriented in a vertical plane. In such avertical scanner, generally all the outgoing scan beams come outsidewards also have an upward vertical component. Objects to be scannedare passed in front of the window with the bar codes oriented in agenerally sideward direction.

In order to produce a successful scan, an object must be oriented withits bar code passed in front of the scan window at an angle which is notso oblique as to prevent a scan line from striking or "seeing" the barcode. Therefore to achieve a successful scan, the user must position theobject with the bar code placed sufficiently close to the desiredorientation. The range of suitable plane orientation of the objectbearing the bar code is limited by the size of the window and the angleover which the mirror array can direct a scan pattern. Present verticalscanners can scan bar codes oriented on certain lateral sides (i.e. sidefacing) which face the vertical window, but experience difficulties inscanning faces oriented in a horizontal plane (i.e., facing up or down)or lateral sides opposite the window. Horizontal scanners (i.e. upwardfacing) are fairly adept at scanning the bottom side but are frequentlylimited as to which lateral sides may be scanned. The present inventorshave recognized that it would be desirable to increase the range ofplane orientation readable by a scanning which would minimize requiredbar code label orientation, support belt to belt (automatic) scanning,and otherwise provide for improved scanning ergonomics.

SUMMARY OF THE INVENTION

The present invention relates to an optical system and method for datareading. A first preferred system is directed to a scanner whichincludes means for generating a first optical beam and a second opticalbeam, the first optical beam being directed toward one side of a firstscanning optical element such as a rotating polygon mirror and to afirst mirror array, the second optical beam being directed toward asecond scanning optical element such as another side of the rotatingpolygon mirror and then to a second mirror array. The first mirror arrayis configured to generate a scan pattern having an apparent source fromone orthogonal direction and the second mirror array is configured togenerate a scan pattern having an apparent source from anotherorthogonal direction. A second preferred system is directed to a scannerhaving a housing with a generally vertical window in an upper housingsection and a generally horizontal window in a lower housing section.The scanner includes a light source generating a light beam and a beamsplitter dividing the light beam into a first optical beam and a secondoptical beam. The first optical beam is directed toward one side of ascanning optical element, then to a first mirror array located in theupper housing section adjacent the vertical window, and then out thevertical window. The second optical beam is directed toward another sideof the scanning optical element with a first portion of the secondoptical beam being directed to a second mirror array located in a firstside of the lower housing section adjacent the upper housing portion andthen through the horizontal window and with a second portion of thesecond optical beam being directed to a third mirror array located in asecond side of the lower housing opposite the first side thereof. In apreferred embodiment, return signals detected from both the first andsecond optical beams are processed by a single microprocessor to allowfor unified signal processing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view of a vertical multiplane scanneraccording to the present invention;

FIG. 2 is a partially diagrammatic right side elevation view of thescanner of FIG. 1;

FIG. 3 partially diagrammatic top plan view of the scanner of FIG. 1;

FIG. 4 partially diagrammatic front side elevation view of the scannerof FIG. 1;

FIG. 5 is a diagrammatic top plan view of the scan pattern along ahorizontal plane generated from the upper mirror array of the scanner ofFIG. 1;

FIG. 6 is a diagrammatic front side elevation view of the scan patternalong a vertical plane generated from the lower mirror array of thescanner of FIG. 1;

FIG. 7 is a schematic diagram illustrating a preferred polygon mirrorscanning and collecting configuration;

FIG. 8 is a schematic diagram illustrating an alternate polygon mirrorlight scanning and collecting configuration;

FIG. 9 is a schematic diagram illustrating another alternate polygonmirror scanning and collecting configuration;

FIG. 10 is a detailed view of the shutter of FIG. 9 taken along line10--10;

FIG. 11 is a schematic diagram illustrating another alternate polygonmirror scanning and collecting configuration;

FIG. 12 is a schematic diagram illustrating another alternate polygonmirror scanning and collecting configuration;

FIG. 13 is a schematic diagram illustrating another alternate polygonmirror scanning and collecting configuration;

FIG. 14 is a schematic diagram illustrating an alternate light scanningand collecting configuration using an pair of movable mirrors;

FIG. 15 is a schematic diagram illustrating a holographic disk lightscanning and collecting configuration;

FIG. 16 is a schematic diagram illustrating an alternate holographicdisk light scanning and collecting configuration;

FIG. 17 is a schematic diagram illustrating a dual holographic disklight scanning and collecting configuration;

FIG. 18 is a flow chart of a preferred light scanning and collectingprocessing scheme;

FIG. 19 is a flow chart of an alternate light scanning and collectingprocessing scheme;

FIG. 20 is a front perspective view of a combination vertical andhorizontal scanner;

FIG. 21 is a top right side perspective view of an alternate multiplanescanner according to the present invention;

FIG. 22 is a simplified schematic of the optics of the scanner of FIG.21;

FIG. 23 is a diagrammatic side view of the internal optics of thescanner of FIG. 21;

FIG. 24 is a side elevation view of the internal optics of the scannerof FIG. 21;

FIG. 25 is a top right side perspective view of the scanner of FIG. 21in partial cutaway;

FIG. 26 is a diagrammatic view of the scan pattern along a verticalplane generated from the upper mirror array of the scanner of FIG. 21;

FIG. 27 is a diagrammatic view of the scan pattern along a verticalplane generated from the lower mirror array of the scanner of FIG. 21;

FIG. 28 is a diagrammatic view of the scan pattern along a horizontalplane generated from the lower mirror array of the scanner of FIG. 21;and

FIG. 29 is a flow chart of preferred light scanning and collectingprocessing schemes for the scanner of FIG. 21.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiments will now be described with reference to thedrawings FIG. 1 is a schematic diagram of a preferred vertical scanner10 having a housing 12 with a lower housing portion 14 and an upperhousing portion 16.

The scanner 10 generates a scan volume generally designated 5 byscanning beams projected outwardly through lower and upper windows 20and 25. In order to facilitate referral to relative directions,orthogonal coordinates (X, Y, Z) are designated in FIG. 1. The Xcoordinate is defined as a sideways direction, perpendicular to orhorizontally outward from the lower window 20 of the scanner housing 12;the Y coordinate is defined as a vertically upward direction; and the Zcoordinate is defined as another horizontal direction parallel to thelower window 20.

FIGS. 2-4 illustrate the internal scanning beam generation andcollection configuration of the scanner 10. The scanner 10 has twowindows namely a lower window 20 and an upper window 25 arranged at anoblique or inclined angle to one another. The scanner 10 may alternatelyhave a single vertical or inclined window, but the dual windowconfiguration provides physical information to the user regarding thedirection of the scanning beams, namely that one scanning beam patternis generally emanating from the upper window 25 and one scanning beampattern is generally emanating from the lower window 20.

The scan engine of scanner 10 has a central rotating polygon mirror 30driven by a motor 40. In the lower housing portion 14, a light source 76generates a beam of light and directs it toward mirror 74. The lightsource 76 may be a laser, laser diode, or any other suitable source. Themirror 74 focuses and reflects light toward the polygon mirror 30 whichhas four mirror facets 31, 32, 33, 34. As the polygon mirror 30 rotates,the outgoing beam is directed across the lower mirror array 80 and thenreflected out through the lower window 20 to achieve a desired scanpattern. Light reflecting off the target returns via the same path andis collected by a collection mirror 72 and focused onto a detector 79.The polygon mirror 30 is preferably molded in a single piece out ofemanating, but could be constructed out of acrylic or other opticalmaterials including other plastics, metals or glass by one skilled inthe art. The outer surface of each mirror facet may be advantageouslycoated with a suitable high reflective coating, the coating chosen woulddepend upon the optical material of the polygon mirror 30. For example,a emanating or acrylic facet may have a metallic coating such asaluminum or gold, while a metal or glass facet may be preferably coatedwith a single or multi-layered dielectric such as silicon dioxide (SiO₂)or titanium dioxide.

The outgoing beam mirror 74 and the incoming collection mirror 72 arealso preferably an integral unit of one-piece construction forming amirror unit 70. Both mirror elements are optically powered, the smalleroutgoing mirror 74 being parabolic and the larger collection mirror 72being ellipsoidal.

Simultaneously (or intermittently if desired) to the operation of thelower scan generation, an upper light source 56 generates a beam oflight and directs it toward mirror 54. The light source 56 may be alaser, laser diode, or any other suitable source. The mirror 54 focusesand reflects light toward the polygon mirror 30. As the polygon mirror30 rotates, the outgoing beam is directed across the upper mirror array60 and then reflected out through the upper window 25 to achieve adesired scan pattern. Light scattered off the target returns the samepath and is collected by a collection mirror 52, reflecting off foldmirror 58 and focused onto a detector 59. The outgoing beam mirror 54and the incoming collection mirror 52 are preferably an integral unit orone-piece construction forming a mirror unit 50. Both mirror elementsare optically powered, the smaller outgoing mirror 54 being parabolicand the larger collection mirror 52 being ellipsoidal.

Outgoing light beam from the upper source 56 reflects off one side ofthe polygon mirror 30 while simultaneously the light beam from the lowersource 76 reflects off an opposite side of the polygon mirror 30. Theupper mirror array 60 cooperates with the rotating polygon mirror 30 togenerate the scan pattern 90 shown in FIG. 5. FIG. 5 is a diagrammatictop plan view of a scan pattern 90 of intersecting scan lines 92 asshown in a horizontal X-Z plane at the base of the scanner 10.

The lower mirror array 80 cooperates with the rotating polygon mirror 30to generate the scan pattern 95 shown in FIG. 6. FIG. 6 is adiagrammatic front elevation view of a scan pattern 95 of intersectingscan lines 97 as shown in a vertical Y-Z plane located at a distance of6.0 in. (15.24 cm) from the scanner 10. From the above description andthe scan patterns disclosed, one skilled in the art may construct asuitable polygon mirror 30 and mirror arrays 60, 80 to achieve thedesired scan patterns.

As shown in FIGS. 2-4, the mirror arrays 60, 80 comprise a plurality ofpattern mirrors arranged generally in what may be described as asemi-circular or oval pattern. The pattern mirrors may be configured toproduce a multitude of desired scan patterns. The scanner 10 projectsscanning sweeps along two generally orthogonal directions, one scanningsweep emanating generally downwardly and sidewardly from the upperinclined window 25 and one scanning sweep emanating generally sidewardlyand upwardly from the vertical lower window 20. It is the cooperation ofthese two scanning sweeps emanating from different scanning directionswhich result in enhanced scanning range. The mirror arrays 60, 80 may bedesigned to produce a desired scan pattern for a particular application.

The upper window 25 is arranged at an oblique angle θ to the verticallower window 20 of about 150°. The lower window 20 and upper window 25are preferably constructed from glass, plastic or other suitablematerial. In an application where it is anticipated objects may strikethe window, it may be coated with a suitable scratch resistant coatingor even constructed of sapphire. The lower and upper windows mayconstitute first and second window elements or may simply be aperturesthrough which the scanning beams pass. The first window element isdefined to be oriented in a first aperture plane and the second windowelement is defined to be oriented in a second aperture plane, the firstaperture plane being oriented at an angle θ to the second apertureplane. Preferably the angle θ is greater than 90° and somewhat less than180°, with a preferred angle of 150°.

Though in actuality the scan patterns generated by each mirror array 60,80 are truly three dimensional, the scanning sweep generated by each ofthe mirror arrays may be generally described as a scan plane, the planebeing defined by a median of scan lines emanating from the respectivemirror array, positioning the plane in a coplanar orientation with thesemicircle of the mirror array. By positioning the mirror arrays 60, 80on opposite sides of the polygon mirror 30, the scan planes emanatingfrom the mirror arrays intersect in the scan volume, the volume throughwhich the objects to be scanned are passed. In an application of avertically oriented scanner in a market checkout stand, the angle of theintersecting scan planes is preferably between about 30° and 90° with apreferred angle of about 60°.

Though the preferred scanning system is described as a fixed scannerwith objects bearing a symbol such as a bar code being passed throughthe scan volume, alternately the scanner and the scan volume may bemoved past a stationary object. Such a configuration may be desirablefor inventory management or large object scanning applications forexample. In either the fixed or moving scanner case, the object is beingpassed through the scan volume.

Alternately, the scanner window (if a single window is employed) or thescanner windows 20, 25 may comprise holographic elements to provideadditional scan pattern directional control. As described above, FIGS.2-4 illustrate a preferred beam generation and collection configuration.That configuration is also diagrammatically illustrated in FIG. 7. Lightsource 56 generates a beam of light onto a small aiming mirror 54 whichfocuses and reflects the light toward one side of the rotating polygonmirror 30 which scans the beam across the upper mirror array. Lightreturning from the target is collected by the collection mirror 52 anddirected toward the detector 59. At the same time, the lower lightgeneration and collecting system generates a light beam from lightsource 76 onto an aiming mirror 74 which focuses and reflects the lighttoward the opposite side of the rotating polygon mirror 30 which scansthe beam across the lower mirror array. Light returning from the targetis collected by the collection mirror 72 and directed toward thedetector 79.

The configuration may also include additional components depending uponthe application. For example, an optical element 58, 78 such as anaperture, filter or grating may be positioned in the outgoing light pathto block out undesirable incoming light rays or provide some otherdesired function.

FIG. 7 illustrates only one preferred beam generation and collectionconfiguration, but other configurations may be implemented. By way ofexample, certain alternate configurations are set forth in FIGS. 8-17and will now be described.

FIG. 8 diagrammatically illustrates an alternate light generation andscanning configuration which employs a single light source 216. Thelight source 216 generates a beam of light through a focusing lens 217which focuses the beam to reflect off a small fold mirror 220 which inturn directs the beam to a beam splitter 224. The beam splitter 224 hastwo functions (a) reflecting a portion of the light toward the polygonmirror 230 and (b) allowing a portion of the light to pass through to bedirected by fold mirror 227 toward another side of the polygon mirror230. On either side of the polygon mirror, the light beam is scannedacross the respective mirror array generating the desired scan patterns.Light returning from the target reflects off the respective mirrorarray, the respective side of the polygon mirror 230, and then reflectsoff beam splitter 224 and mirror 227 and is collected by the collectionlens 222 onto detector 219. In this embodiment having only a singledetector 219, the system may require processing electronics for handlingsimultaneous signals. Alternately, the beam splitter 224 and the mirror227 may be provided with a pivoting means or a shutter may be positionedin one or more of the light paths so that only one incoming beam ispermitted at a given instant. Yet another design may comprise specificalignment of the beam splitter 224 and mirrors 227 and 230 so that onlya single incoming signal is received by the detector 219 at a giveninstant. Yet another alternative design may include a separate detectionsystem for the return beam associated with mirror 227.

Alternately, such a design may be configured with a rotating or pivotingfold mirror (for example in place of the beam splitter 224) which wouldalternately direct the light beam toward the fold mirror 227 or directlyto the polygon mirror 230.

FIGS. 9-10 illustrate an alternate single light source configuration inwhich a light source 236 generates a beam of light which is focused by afocusing lens 234 (optional) and directed by a fold mirror 238 through acombination lens element 244 having a outgoing beam lenslet portion 248and an incoming beam collection lens portion 246. The outgoing beam fromthe fold mirror 238 is focused by the lenslet 248 toward the shuttermirror 250. The shutter mirror 250 is a round shutter element rotated bya motor 258. The shutter mirror 250 has an outer support ring 254 with aportion of its circular surface comprising a reflecting mirror portion252 and the remaining portion being a void 256.

When the mirror portion 252 is aligned in the beam path, the light beamis reflected toward the polygon mirror 240 and returning signal isreflected back to the collection lens which focuses the collected beamonto detector 239. When the void portion 256 is aligned in the beampath, the light beam passes therethrough and is then reflected off foldmirror 242 toward the polygon mirror 240 and returning signal isreflected back off the fold mirror 242, passing through the void portion256 and on to the collection lens which focuses the collected beam ontodetector 239. The relative size of the mirror portion 252 and the voidportion 256 may be selected to adjust the relative amount that the upperand lower scanning is operated. In the preferred embodiment, a majorityof the scanning beam would be directed to the upper scanning portion(e.g. 60%-70%) so the mirror portion 252 would be a larger arc(216°-252°) than the void portion (144°-108°).

FIG. 11 illustrates another alternative light scanning and collectingscheme. Separate light sources 262, 270 each generate a beam of lightwhich is focused by a focusing lens 264, 272 and then passes through anaperture 268, 275 in a concave collecting mirror 267, 274. The lightbeam then is reflected off a respective fold mirror 265, 277 and then toeither side of the polygon mirror 260. Beams are then scanned acrossrespective mirror arrays and reflected signals return reflecting off thepolygon mirror 260 facet, off fold mirror 265, 277 and then arecollected by respective collection mirror 267, 274 to detector 269, 279.One side of the collection system also illustrates an additionalfocusing lens 278 in the light path between the collection mirror 274and the detector 279 to assist in focusing the collected signal beam.

Though the previous embodiments illustrate a single polygon mirror forthe optical scanning element or mechanism, other configurations may beemployed such as for example a rotating optical polygon of any suitablenumber of facet mirrors, a rotating holographic disk, a pair of rotatingsingle facet mirrors, and a pair of pivoting single facet mirrors, orany other suitable scanning mechanism. Some of these alternate designswill now be discussed.

FIG. 12 illustrates a scanning system having a first polygon mirror 284and a second polygon mirror 282 driven by a common motor 280. The firstand second polygon mirrors 284 and 282 may be mounted coaxially on acommon shaft 281. The two light generation and detection schemes areschematically designated as elements 286, 288 and may comprise anysuitable single or dual light source and any suitable light detectorconfiguration such as those already described in the above embodiments.

Similarly, FIG. 13 illustrates a light scanning and collecting schemehaving a first polygon mirror 292 and a second polygon mirror 294arranged side-by-side. The polygon mirrors 292, 294 may be driven by acommon motor through transmission means in the base 290. The two lightgeneration and detection schemes are schematically designated aselements 296, 298 and may comprise any suitable single or dual lightsource and any suitable light detector configuration such as thosealready described in the above embodiments.

FIGS. 12 and 13 illustrate two polygon mirror arrangements, but otherarrangements may be employed. For example, the polygon mirrors may bestacked one on top of the other driven on a common shaft. The mirrors inany multiple mirror configurations may be of different size anddifferent number of facets depending upon the particular application.

FIG. 14 illustrates yet another alternative light scanning andcollecting configuration. In this configuration, the optical scanningelement comprises a pair of pivoting single facet mirrors 308, 318.Light source 300 generates a beam of light onto a small aiming mirror302 which focuses and reflects the light toward pivoting mirror 308which pivots to scan the beam across the first mirror array. Lightreturning from the target reflects off the first mirror array and thenthe pivoting mirror 308 and is collected by the collection mirror 304and directed toward the detector 306. At the same time, the lower lightgeneration and collecting system generates a light beam from lightsource 310 onto an aiming mirror 312 which focuses and reflects thelight toward the pivoting mirror 318 which pivots to scan the beamacross the second mirror array. Light returning from the target reflectsoff the second mirror array and then the pivoting mirror 318 iscollected by the collection mirror 314 and is directed toward thedetector 316.

FIG. 15 illustrates yet another alternative light scanning andcollecting configuration. In this configuration, the optical scanningelement comprises a rotating holographic disk 320 mounted on a motor andsupport frame 321. Separate light sources 322, 332 each generate a beamof light which is focused by a respective focusing lens 324, 334 andthen passes through an aperture 327, 337 in a respective concavecollecting mirror 328, 338. The light beam then is reflected off arespective pivoting fold mirror 326, 336 and then to either side of therotating holographic disk 320. Beams are then scanned, reflecting offrespective fold mirrors 327, 337, across respective mirror arrays towardthe target. Return signals are directed through the holographic disk,off pivoting fold mirror 326, 336 and then are collected by respectivecollection mirror 328, 338 to detector 329, 339.

FIG. 16 illustrates an alternate light scanning and collectingconfiguration employing a single light source 342 which sends a beam oflight toward a small fold mirror 344. Light reflecting off the foldmirror 344 passes through the inner lens portion 347 of lens 346 whichfocuses the outgoing beam toward pivoting or rotating fold mirror 350.Pivoting mirror 350 alternately directs light either toward pivotingfold mirror 352 or pivoting fold mirror 356 depending upon theorientation of the pivoting mirror 350. Light beam from the respectivepivoting fold mirror 352, 356 passes through a respective side of arotating holographic disk 340. Beams passing through the holographicdisk are then scanned, reflecting off respective fold mirrors 354, 358,across respective mirror arrays and reflected signals return beingdirected through the holographic disk, off pivoting fold mirror 352, 356are collected by focusing lens 348 onto detector 359.

FIG. 17 illustrates yet another alternate light scanning and collectingconfiguration, this one employing first and second holographic disks360, 370. The two light generation and detection schemes areschematically designated as elements 362, 372 and may comprise anysuitable single or dual light source and any suitable light detectorconfiguration such as those already described in the above embodiments.The first and second holographic elements 360, 370 may be mountedseparately and driven by separate motors, but preferably as illustratedmay be mounted on a common axis or shaft 368 and rotatably driven by asingle motor 366. The light beam from the first element 362 is directedthrough the first holographic disk 360 and reflected off the fold mirror364 and scanned across the first mirror array. Similarly, the light beamfrom the second element 372 is directed through the second holographicdisk 37 and reflected off the fold mirror 374 and scanned across thesecond mirror array. Return beams follow the same path and are detectedin respective collection elements.

The above described scanning and collecting configurations are but a fewexamples of suitable configurations. Following the disclosure herein,one skilled in the art may combine portions of some of theconfigurations with other of the configurations.

FIG. 18 is a flow chart of a preferred light scanning and collectingprocessing scheme. A first (bottom) laser diode light source 107 andsecond (top) laser diode light source 105 generate light beams toward arespective bottom scan head 112 and top scan head 110. Scan beams fromboth the top scan head 110 and the bottom scan head 112 are reflectedoff a common facet wheel 115 or polygon mirror. Since the design mayemploy a common polygon mirror, the system requires only a single motorassembly resulting in reduced unit size, weight and cost as well aspower consumption. Return signal is collected at top and bottomcollection optics 120 and 122, with the signals processed in respectiveanalog signal processing units 125, 127 and then converted and processedin respective digital processors 130, 132. The processed raw data fromboth digital processors 130, 132 is then input into a firstmicroprocessor 135 where the signals are analyzed and processedtogether. This common processing allows for enhanced efficiency andscanning advantages. For example, a partial bar code scanned by a scanline generated from the top scan head 110 and collection optics 120 maybe stitched together with a partial bar code scanned by a scan linegenerated from the bottom scan head 112 and collection optics 122 toachieve a complete scan. A second microprocessor 140, which may beseparate from or included within the first microprocessor 135, mayoptionally integrate data input from a weigh scale 197. Once processed,data from the processor 140 is output to an application systemillustrated as the point of sale system 195.

FIG. 19 is a flow chart of an alternate light scanning and collectingprocessing scheme. A first (bottom) laser diode light source 157 andsecond (top) laser diode light source 155 generate light beams toward arespective bottom scan head 162 and top scan head 160. Scan beams fromboth the top scan head 160 and the bottom scan head 162 are reflectedoff a common facet wheel 165. The return signal is collected at top andbottom collection optics 170 and 172, with the signals processed inrespective analog signal processing units 175, 177 and then input into amultiplex timer circuit 180 so that the bar code signals from the topand bottom may be successively combined and transmitted to the decodingI/F electronics unit 185. This common processing allows for enhancedefficiency and scanning advantages similar to the previous embodiment.The decoding microprocessor 185 may optionally integrate data input froma weigh scale 147. Once processed, data from the processor 185 is outputto the point of sale system 145.

The scanning system may also be combined with a horizontal scanner. FIG.20 illustrates a combination vertical and horizontal scanner 410. Thescanner 410 includes a housing 412 with a lower housing portion 414, anupper housing portion 416, and a lower horizontal housing portion 418.The scanner 410 generates a scan volume from four sets of scan linesprojected from different generally orthogonal directions, a first set ofscan lines emanating downwardly and sidewardly from a first mirror array490 through the upper inclined window 425, a second set of scan linesemanating sidewardly from the second mirror array 480 through thevertical window 420, a third set of scan lines emanating generallyupwardly and sidewardly from a third mirror array 470 through horizontalwindow 427 (away from the upper housing portion 414), and a fourth setof scan lines emanating generally upwardly and sidewardly from a fourthmirror array 460 through horizontal window 427 (toward the upper housingportion 414).

Alternately, the scanning systems of FIGS. 1 or 20 may also be combinedwith a scale unit or a combined scale-scanner unit. In one alternateembodiment, element 427 may be a weigh scale unit providing weight dataand as set forth in the flow chart of FIG. 18 for example, the inputfrom the scale electronics 147 may be sent directly into themicroprocessor 140. In yet another alternate embodiment, element 427 maybe a combined weigh scale and scanner unit providing both a thirdscanning sweep and weighing capability. One such combined scale andscanner is disclosed in U.S. Pat. No. 4,971,176 which is herebyincorporated by reference.

An alternate multiplanar scanner is illustrated in FIGS. 21-39 showing ascanner 500 having a housing 510 with a lower horizontal housing portion512 and an upper housing portion 516. The scanner 500 has two windowsnamely an upper window 520 arranged in a generally vertical plane and alower window 525 arranged in a generally horizontal plane. The upperwindow 520 and the lower window 525 are arranged at a generally rightangle to one another.

FIGS. 22-25 illustrate a preferred optical configuration for the scannerof FIG. 21. A single light source shown as a visible laser diode 535generates an optical beam 515 which is collimated and directed towardbeam splitter 538. The beam splitter 538 splits the ortical beam.515into a first beam 517 and second beam 518 thereby creating a means forproducing multiple beams. As shown in previous embodiments, the meansfor producing the first and second beams 518 and 517 may be comprised ofseparate light sources (see e.g. FIG. 7 in which the separate lightsources are comprised of first and second laser diodes 56, 76) or asingle light source (see e.g. single leaser diode 535 and beam splitter538 of FIG. 22). The first beam 517 is directed to a fold mirror 536which reflects the beam 517 through a central lens focusing portion 533in lens 532 and to rotating optical polygon 530. The optical polygon isrotated by a motor 590 with its speed controlled by a suitablecontroller. The optical polygon 530 includes three mirror facets forproducing three different scan lines scanning the optical beam acrossthe pattern mirrors. More facets may be employed and the facet wheel mayscan the beam along the same path but different paths are preferred inthis embodiment to achieve better coverage of scan lines. As the beam517 is swept across the upper mirror array, a first set of scan lines isproduced. The upper mirror array is comprised of mirrors 586, 588located in the upper housing section 516 adjacent the vertical window520. Routing mirrors 580, 581, 582, 583, and 584 route the scanning beamfrom the optical polygon 530 to the upper mirror array 586, 588. Withthe mirror facets on the spinning polygon mirror 530 positioned atdifferent angles, each routing mirror(s)/array mirror combination willgenerate three scan lines per revolution of the polygon mirror 530.

FIG. 26 is a diagrammatic side view of a scan pattern 610 ofintersecting scan lines as shown in a vertical Y-Z plane in front of thevertical window 520. This first set of scan lines 610 emanates generallysidewardly through the vertical window 520. The pattern of the scanlines 610 are formed as shown in the following table:

    ______________________________________                                        Routing mirror(s)                                                                            Array mirror                                                                            Scan lines                                           ______________________________________                                        584            588       611, 612, 613                                        583            586       614, 615, 616                                        583            588       617, 618, 619                                        582            586       620, 621, 622                                        580, 584       588       623, 624, 625                                        581, 582       586       626, 627, 628                                        ______________________________________                                    

FIG. 27 is a diagrammatic side view of a scan pattern 630 ofintersecting scan lines as shown in a vertical Y-Z plane in the scanvolume facing away from the vertical window 520. This second set of scanlines 630 emanates generally sidewardly and upwardly through thehorizontal window 525 toward the vertical window 520. The lines of thescan pattern 630 are formed as shown in the following table:

    ______________________________________                                        Routing mirror                                                                              Array mirror                                                                            Scan lines                                            ______________________________________                                        566           554       631, 632, 633                                         572           552       634, 635, 636                                         578           552       637, 638, 639                                         568           556       640, 641, 642                                         ______________________________________                                    

FIG. 28 is a diagrammatic top view of a scan pattern 650 of intersectingscan lines as shown in a horizontal X-Z plane in the scan volume facingthe horizontal window 525. This third set of scan lines 650 emanatesgenerally upwardly and laterally sidewardly through the horizontalwindow 525 with scan lines 651-656 being perpendicular to the plane ofthe vertical window 520 and scan lines 657-622 being primarily forbottom scanning being toward the vertical window 520. The lines of thescan pattern 650 are formed as shown in the following table:

    ______________________________________                                        Routing mirror                                                                              Array mirror                                                                            Scan lines                                            ______________________________________                                        564           560       651, 652, 653                                         562           558       654, 655, 656                                         576           552       657, 658, 659                                         574           552       660, 661, 662                                         ______________________________________                                    

FIG. 28 also shows the second set of scan lines 630 as they are visibleand provide additional scanning coverage in the horizontal plane such asfor scanning the bottom surface of an object being passed through thescan volume.

Moreover, each of the lateral sides of an object being passed throughthe scan volume may be scanned by lines from more than one of the setsof scan lines. Assuming an orientation of the scanner 500 with theproduct being moved through the scan volume along the "Z" direction(shown in the X, Y, Z directions in FIG. 21), the face of the objectwould be scanned primarily by lines 654-656 from the third set of scanlines 650 through the horizontal window 525 but also by lines 631-633from the second set of scan lines 630 through the horizontal window 525and by lines 620-622 and 626-628 from the first set of scan lines 610through the vertical window 520. Thus a dense coverage of scan lines isachieved for all lateral sides of an object being passed through thescan volume.

FIG. 29 is a flow chart illustrating the preferred scanning method. Alight source 535 generated a beam of light 515 which is divided by abeam splitter 538 into a first beam 517 and a second beam 518.Preferably the beam splitter 538 transmits 40% of the beam to one sideof the facet wheel 530 which scans the beam 517 across the first set ofpattern mirrors M₁ for scanning through the vertical window 520 and 60%of the beam is reflected and directed to the opposite side of the facetwheel 530 and scanned across the second and third sets of patternmirrors M₂ and M₃. The portion of the scanning beams returning via thethe first set of pattern mirrors M₁ reflect back off the facet wheel 530and are collected by collection optics namely collection lens 532,collection folding mirror 531 and analog PCB with photodiode 537. Theportion of the scanning beams returning via the second and third sets ofpattern mirrors M₂ and M₃ reflect back off the facet wheel 530 and arecollected by collection optics namely collection lens 540, collectionfolding mirror 544 and analog PCB with photodiode 546.

The separate collection optics permit the simultaneous scanning throughthe horizontal and vertical windows. Separate analog signal processors710, 712 are provided for simultaneously processing the analog signalsfrom the respective photodiodes. Each signal is then converted andprocessed in a digital processor 714, 716 and then input into themicroprocessor 725 for final processing and transmittal to the point ofsale system 730. Alternately, the signals from the analog signalprocessors 710, 712 may be routed to a single digital processor 720,multiplexed by a switching mechanism 713. Alternately, a combination ofthe above two embodiments may be used. Buffers (not shown) may be usedin the above embodiments.

An integrated weigh scale may be incorporated into the horizontalhousing portion 512. Such a system is preferably constructed with aconcentric beam system which does not interfere with the placement ofthe horizontal window 525 at the center of a weighing platter. Thesignal from the scale electronics 740 may then be transmitted to themicroprocessor 725 for processing and output to the POS system 730.

Thus, a scanning system and method for reading data have been shown anddescribed. It is intended that any one of the disclosed outgoing lightconfigurations may be combined with any one of the collectingconfigurations. Though certain examples and advantages have beendisclosed, further advantages and modifications may become obvious toone skilled in the art from the disclosures herein. The inventiontherefore is not to be limited except in the spirit of the claims thatfollow.

What is claimed is:
 1. A scanner for reading symbols on an object beingpassed through a scan volume, comprising:a housing includinga firsthousing section having a first window which is oriented horizontallybelow the scan volume, a second housing section connected to the firsthousing section, the second housing section having a second window whichis oriented generally vertically to a lateral side of the scan volume, athird housing section having a third window which is oriented obliquelyto a lateral side of the scan volume; an optical scanning element withinthe housing; at least first and second optical beams which are directedfrom different directions onto the optical scanning element to produce(a) a first set of scanning beams being directed out the first window,(b) a second set of scanning beams being directed out the second windowand (c) a third set of scanning beams being directed out the thirdwindow.
 2. A scanner according to claim 1 further comprising patternmirrors for directing the first, second and third sets of scanning beamsthrough the respective first, second and third windows.
 3. A scanneraccording to claim 2 wherein the pattern mirrors comprise a first mirrorarray positioned in the first housing section adjacent the first window,a second mirror array positioned in the second housing section adjacentthe second window, and a third mirror array positioned in the thirdhousing section adjacent the third window.
 4. A scanner according toclaim 1 wherein the second housing section has a top portion, the thirdhousing section being connected to the top portion of the second housingsection, wherein the third window is positioned above the scan volume.5. A scanner according to claim 4 wherein the first set of scanningbeams is projected in an upwardly direction out the first window, thesecond set of scanning beams is projected in an sidewardly direction outthe second window, and the third set of scanning beams is projected inan downwardly direction out the third window.
 6. A scanner according toclaim 1,wherein the first set of scanning beams directed out of thefirst window optically sense a first portion of the symbol on the objectwhich is less than the entire symbol and generating a first signalresponsive to the sensed variations in light reflectivity of said firstportion, wherein the second set of scanning beams directed out thesecond window optically sense a second portion of the symbol on theobject which is less than the entire symbol and generating a secondsignal responsive to the sensed variations in light reflectivity of saidsecond portion; wherein the scanner further comprises a processor unitfor processing the first and second signals to determine informationcontained in the symbol by combining at least the first and the secondsignals to fully decode the information contained in the symbol.
 7. Ascanner according to claim 1 wherein the optical scanning elementcomprises a polygon mirror having mirrored facets for reflecting thefirst and second optical beams in a plurality of directions.
 8. Ascanner according to claim 1 further comprising a plurality of patternmirrors for reflecting the first set of scanning beams through the firstwindow to produce a first scan pattern consisting of a plurality ofintersecting scan lines, for reflecting the second set of scanning beamsthrough the second window to produce a second scan pattern consisting ofa plurality of intersecting scan lines, and for reflecting the third setof scanning beams through the third window to produce a third scanpattern consisting of a plurality of intersecting scan lines.
 9. Ascanner according to claim 1 wherein the third set of scanning beams aredirected diagonally into the scan volume.